Fulcrum adjuster



Feb. 17, 1959 c. R. KILGORE 2,873,730

FULCRUM ADJUSTER Filed July 2, 1957 2 Sheets-Sheet 2 L21? IzZb 2 Charles.72. [Ci/ yore States Patent 2,873,730 FULCRUM ADJUSTER Charles R.Kilgore, Cleveland, Ohio, assignor to Thompson Products, Inc.,Cleveland, Ohio, a corporation'of Ohio a I 1 Application July 2, 1957,Serial No. 669,512 17 Claims. (Cl. 123-90) The present invention relatesto improvements in lash adjusters for engine valve linkages. Moreparticularly, the invention relates to an improved oil operatedmechanism whichprevents excessive and objectionable lash in theoperation of engine valves wherein the lash adjuster or preventer ismounted on an engine to pivotally support 2 ber remains stationary and acentral plunger oscillates during engine operation.

A further object of the. invention is to provide a las preventer andfulcrum adjuster wherein only .one dynamic seal is required therebyreducing drag and speeding recovery during starting and improving lowtemperature operation. v

An object of the invention is to provide an improved piston and cylindertype fulcrum adjuster with improved oil delivery to the pressure chamberunder both starting conditions and runningconditions, and wherein acontrolled escape flow of oil is permitted from the pressure chamberduring a valve opening stage of operation with a positive replenishmentof oil during a valve closing stage of operation. J I

' A further object of the invention is to provide an improved lashpreventing fulcrum adjuster for an overhead valve linkage wherein afluid supply may be received'from a sealed reservoir with built inpressurizing means.

end with the reciprocating stem of a valve. The rocker arm may have anopening through the depressed. portion for the passageof a mounting studor post projecting upwardly from the'engine and serving to support thelash adjusting unit. The stud or post may be provided with an oilpassageway theretbrough communicating with the pressurized oil supply ofthe engine to deliver pressurized oil to the lash adjusting unit, or inone form, the unit is self-sufficient- An'object of the invention is toprovide an improved lash preventing mechanism for pivotally supportingthe rocker arm in an engine valve linkage wherein the mechanism isutilized as an integral unit for improved operation and simplicity ofhandling and assembly.

Another object of .the invention is to provide a lash preventingmechanism which serves as a fulcrum adjuster for the rocker arm of anengine valve linkage.

Another object of the invention is to provide a fulcrum adjuster for anengine valve linkage wherein the operating clearances are simply and"readily adjusted according to the requirements of the engine without'thenecessity of providing close manufacturing tolerances.

Another object of the, invention is to provide an improved lashpreventing device and fulcrum adjuster which is provided with aninternal engine oil reservoir for improved operation during starting.

A further object of the invention is to provide an improved fulcrumadjuster wherein entrapped air is removed from the oil and is preventedfrom reaching the high'pressure chamber.

Another object of the invention is to provide a fulcmm adjuster in'whichan oil leak-down passage is provided and wherein the passage can beconstructed to-be annular proved fulcrum adjuster wherein the outerbarrel mem- Other objects and advantages will become more apparent withthe disclosure and teaching ofothe principles of the invention inconnection with the description of the preferred embodiment in thedrawings, specification and claims, inwhich:

Figure 1 is a vertical. sectional view taken through a valve assemblyemploying a fulcrum adjuster of the pres ent invention; v

Figure 2 is a plan view of the top of the rocker arm, somewhat enlargedfrom Figure. 1,, and with the valve and engine block removed;

Figure 3 is an enlarged verticalsection taken through thefulcrum'adjuster assembly;

' Figure 4 is an enlarged side elevational view of the fulcrum adjusterin position supporting the rockerarm with a portion of the fulcrumadjuster housing broken y; A

Figure 5 is an enlarged fragmentalsectional view of the fulcrum adjusterillustrating the operationof the oil valve during the' time the oil isbeing'r'eplenished to the pressure chamber; I

Figure 6 is an enlarged fragmental sectional view similar to Figure 5,and illustrating theposition of the valve during starting of the engine;and,

Figure 7 is a vertical sectional view taken through a fulcrum adjustermechanism of another form.

Although the fulcrum adjuster mechanism is shown in its preferred formsas utilized for preventing valve lash of an engine-valve linkage, itwill be understood that the principles of the invention may be utilizedin other environments, taking advantage of their inherent features anduses.

In the'valve linkage-assembly shown in Figures 1 and 2, the internalcombustion engine is shown generally at 10, and includes a cylinder,block 11 with a cylinder head 12. The head 12 has a guide 13 receivingin slidable relation therein the stem 14 of the poppet valve 15.

- The head 16 of the valve cooperates with the seat' 17 in the enginehead 12 to control the flow of gases be tween the valve port '18 andthecombustion chamber 19.

The upper end of the valve stem 14 has grooves 20 thereon, and theconventional split valve locks 21 have beads which seat in thesegrooves. A valve spring retainer 22 is fixedly held on the upper end ofthe valve stem by the locks 21 which are tapered, and a valve spring 23surrounds the valve stem and has one end bottomed on the retainer 22 and:the other end bottomed on the shoulder 24: of the engine head 12surrounding the guide 13. .The valve stem 23 is thus biased to hold thevalve 16 against its seat 17.

The rocker arm is shown in the form of a stamped sheet metal arm 25having a depressed fragmental spherical socket portion 26 in the bottomthereof with an aperture 27 through the bottom of the socket. The rockerarm is surrounded by an upturned peripheral flange 28 to have agenerally bowl-shaped interior 29. At one end ofthe rocker arm and atone side of the socket 26, the bottom of the bowl 29 is raised toprovide an inverted socket 30 for the rounded end 31' of a push rod 32.The push rod 31 can rock in the socket 2t] and oil aperture 33 isprovided through the socket to lubricate the end 31 of the push rod. Onthe opposite side of the socket 26 and on the opposite end of the rockerarm, the bowl: shaped bottom portion 29 of the rocker arm is depressedat 34' to provide a round exterior for engaging and rocking on'the end35 of the valve stem 14.

Q In accordance with this invention, the rocker arm is: pivotallysupported. in its operating position on the engine valve head 12 bymeans of an automatic lash adjuster or preventer or an automatic fulcrumadjuster, such as is shown generally at 36.

The fulcrum adjuster 36 is supported in its operating position topivotally carry the rocker arm. 25, on a post 38 which is suitablyattached to the engine head 12 and may be threaded into an opening 40 atthe top of the 7 engine head 12. In this location, thepost 38communicates with an oil ehamber42, which is supplied with pressurizedoil from the oil pump of the engine. The pressurized oil is fed upthrough the centerv of the post which has a coaxially centrallyextending oil passageway 44 to pressurize the oil pressure chamber 46 ina manner which will be described.

As illustrated in Figure 3, the supporting post 38 has a smoothcylindrical exterior to slidably receive the bearing member 47.The-bearing member 47 likewise has a smooth cylindrical interior bore 48extending therethrough .in order to slidably move on the post. The bore48 is slightly largerthan the exteriorssurface 44 of the post, so as toform an oil leak-down passageway 50. The bearing member 47, which isslidably positioned on the post 38, is also slidably received by thereaction member 54. The reaction member 54 may be of a stamped orpressed steel cup or the like and has a cylindrical interior 56. At itsupper end 57, the reaction member or cup 54 is turned inwardly over thetop of the bearing member 47 to meet the post 38 and has .a circularhole 58, through which the upper end of the post 38 passes. Theturned-in top portion 57 of the reaction member-.54 forms a shoulderagainst which presses a nut 60 and a washer 66 to determine the positionof the reaction member 54011 the post. The nut may be used without awa'sherif desired and is carried on the threaded upper -end 68 of thepost and may be adjustably turned up or down to fix the operatingposition of the reaction member. Thus, this adjustment can be madeeasily and it is not necessary that the post 38 be provided withaccurate-manufacturing tolerances, and the position of the fulcrumadjuster unit 36 can be readily set in accordance with the conditionspresented by the rocker arm 25 and its associated valve 15 and push rod32.

It will be seen from the drawings, that the bearing member 47 and thereactionmember 54 which is telescoped over the top thereof, form acompactunit cartridge which issimple to'handle and assemble. To maintainthe bearing 47 and reaction member 54 together, the lower edge ofthecup=shaped reaction member is staked, such as at locations 70 and 72,shown in Figures 1, 3 and 4.

.The reaction member 54 andthe bearing member 47 form the oil pressurechamber-46 between them wherein the pressurized oil urges the bearingmember 47 to extended position with respect to the reaction member 54'asit is fixed in position by thenut 60 at the top of the post 38. Thelower end of the oil pressure chamber-464s closed by a dynamic seal 74,shown in the shapeof 'anannular sealing ring which may be ls-shaped incross section. The base 76 of the ring seats against a shoulder 78formed on the bearing member 47. The outer leg 80 of a dynamic seal 74rides against the inner cylindrical wall 56 of the reaction member 54.The dynamic seal is held against the shoulder 78 by the valve supportspring 82 which is a spiral coiled compression spring located in thepressure chamber 46.

The upper end of the pressure chamber 46 is defined by the annularsleeve 84, which is press fit within the cup-shaped reaction member 54.I M

The sleeve 34 has an upwardly extending flange. 86 at its upper endwhich meets the inwardly turned flange 57 at the top of the cup todefine an oil reservoir 88.

This oil reservoir communicates with the oil pressure chamber 46 througha plurality of axially drilled oil passageways leading downwardly fromthe reservoir 88 to the pressure chamber 46 past the annular fluidtransfer valve ring 92. The sleeve 84 has an annular oil distributiongroove 94 in its lower. face which permits communication between thefluidpassageways 90 and overiwhich is positioned the movable valve ring92' The valve ring is held in place by a wave spring 96 which bearsagainst its lower surface holdingj'it upwardly in position over thegroove 94. The valve supporting wave spring 96' is supported on a valvesupporting ring 98, which has an annular upper vertical flange holdingthe wave spring 96 and the valve ring 92' radially in place, and whichhas a lower horizontal flange against which bears the valvesupportingspring 82 to support the valve spring vertically.

' The operation of this assembly is illustrated in Figures 5 and '6.During normal running operation, when the valve 15. is closing, the oilpressure in the reservoir 88 will be greater than the pressure in thepressure cham ber 46. The valve ring 92 will then open to the positionshown in Figure 5 whereupon the oil will flow through the passageway 99down into the pressure chamber 46.

During periods of time when the engine" is stopped, the bearing member47 will collapse against the reaction member '54 to the position ofFigure 4, if the engine is stopped with corresponding engine valve 15'open. When the engine starts, oil is pumped from the pressure systeminto the reservoir 83' and will quickly fill into the pressure chamber46. To permit this rapid filling, the valve supporting spring 82 willcompress to permit the valve ring 92 and its valve spring 96 to movecompletely away from the groove 94 for a rapid .flow of oil. Thisposition is shown in Figure 6, and it will be seen that valve ring 92.can open much further when the spring 82 is compressed, than when onlythe spring 96 is compressed, as is the case in Figure 5.

To supply .oil to the reservoir 88, oil flows up through theraxialoiLsupply bore 44 in the center of the post 38 and outwardly through thelateral passages 100, which extend laterally through the top of the posttocommunicate between the central bored passageway 44 and the smallchamber 102 .formed between the post 38 and the top of a tubularextension .104 which projects upwardly from the top of the.bearingmember v47. The-oil will normally flow over the top of thetubular extension 104 when the .parts are in the position of Figure 3,whichis the operating position. .Av series of rounded notches 106 arecut in the top edge of the tubular extension 10.4 so that oilcan flowover the top of this tube when the parts are collapsed, asshown inFigure4, due .to' the-:engin'e beingstopped with;a correspondingenginevalve. 15.open. The oil then flows over the top of the flange orwall 86of the sleeve 84 through the curved notches 10'8'ii1 the top of the wallto thus enter the oil reservoir 881 The first pressurized'oil thatreachesthe adjuster after prolonged shut down of the engine containsquantities'of entrained air. The present invention prevents the airimpregnated oil from entering the high pressure dham'ber ofthe adjusterand means are provided'jtoremove theair.

., i for this purpose, the small chamber 102, which intercepts't he oilbefore it reaches the reservoir or the pressure chamber, has acommunicating vent 110. This vent re eeives thebubbles of air which risefrom the oil in the reservoir 88 and flow out'through the vent 110. Thevent is formed by the space between the threads 68 of the post and theopening 58 at the top of the reaction barrel 54. The vent is completedby a slot 112 through the side of the washer 66. If no washer is used,the slot will be found in the lower face of the nut. This vent issufficiently small to prevent the escape of an appreciable amountof oil,but permits the escape of the bubblesof air and prevents them fromreaching the pressure chamber 46. Theoil that does escape duringrunningoperation runs down over the outside of the adjuster 36 and lubricatesthe surface 52 of the bearing member.

The small intermediate chamber 102 also co mmunicates with the oilleak-down path 50 which is formed between the inner surface of the bore48 through the bearingmember 47 and the outer cylindrical surface 44 ofthe 'post38. This space or path is completed'by the tubular extension104 which projects upwardly from the base of the bearing member 47.

When the engine valve stem 14 is being pushed downwardly by the push rod32 being raised, the pressure within the pressurechamber 46 becomesgreater than the pres sure within the engine oil system, which is thepressure within the reservoir 88. The valve ring 92 closes but acontrolled escape of oil is permitted through an oil escape path 114defined between the outer surface of the tube 104 ahdthe inner surfaceof the sleeve 84. This slow escape or bleed of oil is not 'suflicient topermit the parts to-collapse and the rocker arm will be held downwardlyby the oil within the pressure chamber 46. When the engine valve closes,the pressure in the pressure chamber '46 will drop below the pressurewithin the oil system of the engine so that a replenishing supply'of oilis fed the' pressure chamber past the valve ring 92. In Figure 7 anotherform of the unitary fulcrum adjuster is shown at 36a. The fulcrumadjuster unit is illustrated as carried at the top of a post 38awhich'may or may not be bored with a central oil passageway for supplymgoil to the fulcrum adjuster. In the form illustrated,

the adjuster has no external source of oil and operates from afixedsupply contained within the reservoir 88a.

The adjuster includes a bearing member 47a which pivotally supports therocker arm 25a and which is slidably mounted on the post 38a. The innersurface, 48a of the bearing member slides against the outer surface 44aof thepost. I

An oil pressure chamber 46a is defined between the bearing member 47aand a reaction member 54a. The reaction member has a cylindrical shapedbarrel 55a which turned inwardly at its top 57a to form -a cupshapedelement. The'barrel is staked as at 72a to catch beneath the flange 77aon the bearing member 47a to hold thebarrel 55a and bearing member 47atogether.

The barrel 55a contains a central threaded opening 116 which permits thebarrel to be threaded onto the top 68a of the post. Thus, the positionof the fulcrum adjuster unit can easily be controlled by threading theentire barrel 55a up or down on the post.

The oil reservoir 88a communicates with the pressure chamber 46a throughoil-passageways 90a. Flow .of oil through the oil passageways iscontrolled by a valve ring 92a held in place by a wave spring 96a, whichis carried on a support 98a that is held at the top .of the valvesupport'spring 82a. The pressure chamber is sealed by dynamic seal 74aand a small oil bleed path 114a -is provided between the tube 104a whichextends upwardly from the bearing member and the annular sleeve 84a,which is fixed within the barrel 55a. I

Thus, as the engine valve-is opened and the pressure withinthe pressurechamber 46a increases, a small leakin Figure 6.

This oil is replaced in the"press'ure chamber 46divhcn the engine-valvecloses, by the oil being forced downwardly 'through the passageways apast the ring valve 92a.

Oil pressure is maintained within the reservoir 88a by aspring backedreservoir seal 118. This seal 118 is located slidably between the innercylindrical surface 56 of the barrel 55a and the outer cylindricalsurface of the tube 10411. The seal has an annular backing ring A coilcompression spring 122 extends between the backing ring 120 and the topof the barrel 57a, thus maintaining a pressure within the reservoir 88a.

Thus, the unit of Figure 7 is entirely self-contained and requires noexternal supply of oil.

Although the operation of the fulcrum adjuster in combination with thevalve linkage will be clear from the description of the individualelements, a brief sum-1 many of operation will be helpful inunderstanding the features and advantages. The fulcrum adjuster or lashpreventing unit 36 is shown in its collapsed position in Figure 4, as itwill appear after a shut down period of the engine if the engine stoppedwith the engine valve 15 open. The tube 104 engages the upper end 57 ofthe barrel 55 of the reaction member 54. When the engine is started, oilwill flow upwardly through the central bored passageway 44 of the post38 and outwardly through the lateral passageways 100. The pressurized'oil will pass through the curved notches 106 at the top of the tube 104and through the notches 108 'at the top of the sleeve insert 84 to enterthe reservoir by the slot 112 in the washer 66. Thus, air-free oil willpass downwardly into the passageways 90 to the pressure chamber 46. s

Upon starting, the oil will quickly fill the pressure chamber 46 byforcing the ring valve 92 away from the groove94, compressing spring 82in the manner shown When the pressure chamber 46 is filled, and duringoperation, as the rocker. arm 25 is rocked to open the engine valve, thevalve ring 92 will close and a small bleed of oil will flow upwardlythrough the annular path 114. When the engine valve stem is released,the pressure in the pressure chamber 46 will drop below the pressure inthe reservoir 88 and a replenishing supply of oil will flow through thepassageways 90 past the ring valve 92. Thiscycle of operation continuesfor each opening and closing of the valve and the rocker arm. will besupported to pivot about its fulcrum, as established by the bearingmember 47.

Thus, it will be seen that I have-provided an improved fulcrum adjusterwhich operates to prevent objectionable valve lash and which-meets theobjects and advantages hereinbefore set forth. The adjuster forms aunitary cartridge which is self-contained and is easily assembled on theengine. Adjustment of the position of the adjuster is easily obtained bythreading the adjuster itself to the'top of a supporting post or bythreading the nut onto the poston top of the adjuster.

The adjuster is provided with an annular oil bleed or leakage path fromthe pressure chamber to maintain a movement of oil through the pressurechamber during the operation of the mechanism. The lubricating oilleak-down path is also annular in shape and smaller in age of oil passesupwardly through a bleed path 114a. fl prevented from reaching thepressure chamber.

I have, in he d ng nd p cifica ion pre n ed a detailed disclosure ofthepreferred embodiments of my invention, but it is to be understood that Iassist in tend to limit the invention to the specific form disclosed,butuntend to. cover all modifications, changes, and alternatrveconstructions and methods falling within the scope of the principlestaught by my invention.

I claim as my invention: 1. A lash preventing device for a valveoperating linkage having a bearing surface for pivotally supporting arocker arm whereby the rocker arm is held in non-lash engagement withits operating push rod and operated valve stem comprising a bearingmember adapted to pivotally support a valve rocker arm, a reactionmemher having a hollow cylindrical interior for slidably receiving thebearing member and defining an oil pressure chamber within the interiorwhereby the bearing memher is urged in a direction to prevent valvelash, a sup porting post extending upwardly from the engine and passingthrough the bearing member whereby the bearing member slidablyreciprocates on the post, a narrow cylindrical oil escape passagewaydefined between the hearing member and the reaction member andcommunicating with the pressure chamber for the controlled escape of oilwhen the rocker arm exerts a pressure on the bearing member, an oilsupply passageway leading to the pressure chamber for the supply of oilto the pressure chamber for replenishing oil lost through the escapepassageway, and, valve means in the oil supply passageway preventing theescape of oil when the engine valve is being opened and the rocker armexerts a reaction force on the bearing member and opening the valve topermit replenishing oil to the pressure chamber when the engine valve isclosing and the reactive force between the rocker arm on the bearingmember diminishes.

2. A device for preventing lash in engine valves operated by a rockerarm comprising a rocker arm support having a bearing for pivotallycarrying the rocker arm, a reaction member cooperatively forming an oilpressure chamber with said rocker arm support for urging a rocker armcarried by the support into lash preventing engagement with its push rodand valve stem, a threaded post projecting from the engine for carryingthe reaction mem ber, and threaded means coacting with the post andadjustably fixing the position of the reaction member and located in afixed location relative to the post for each adjusted operating positionof the reaction member, the threads otsaid post extending beyond. saidthreaded means a substantial distance whereby adjustment may be madebeyond said operating positions.

3. A device for preventing lash in engine valves operated by a rockerarm comprising a rocker arm support having a bearing for pivotallycarrying the rocker arm, a reaction member support cooperatively formingan oil pressure chamber with said rocker arm support for urging a-rockerarm cairied by the support into lash preventing engagement with its pushrod and valve stem, a post extending through 'said members from theengine, biasing means urging the members apart, and a nutthreaded to thepost and bearing against one of said members whereby said member may beadjustably positioned with respect to the other member.

4. A mechanism for pivotally supporting an engine valve rocker arm innon-lash relationship to coacting operating parts comprising a bearingmember adapted to pivotally support a rocker arm, a cooperating reactionmember coacting with the bearing member, with the surfaces of thereaction member and bearing member defining a pressure chambertherebetween urging the rocker arm to non-lash position, said surfacesalso defining a closed reservoir in communication with the pressurechamber whereby a supply of oil will be available, and

,means to carry the reaction member in an operating position.

5. A mechanism for pivotally supporting an engine valve rocker arm innon-lash relationship "to coacting operating parts comprising a bearingmember adapted to pivotally support a rocker arm, a cooperating reactionmember coacting with the bearing member and the surfaces of the reactionmember and bearing member defining a pressure chamber therebetween forurging the rocker arm to non-lash position, conduit means 'for supplyingpressurized oil to the pressure chamber to force the members apart, andvent means communicating with the conduit means whereby air entrained inthe oil is permitted to escape.

6. A mechanism for pivotally supporting an engine valve rocker arm innon-lash relationship to coacting operating parts comprising a bearingmember adapted to pivotally support a rocker arm, a cooperating reactionmember coacting with the hearing member and the surfaces of thc reactionmember and bearing member dc fining a pressure chamber therebetween forurging the rocker arm to a non-lash position, means defining an oilsupply reservoir communicating with the pressure chamber, and a ventpassageway in communication with the reservoir whereby the air in oilsupplied to the reservoir may escape.

7. A device for preventing lash in engine valves operated by a rockerarm comprising a rocker arm support having a bearing for pivotallycarrying the rocker arm, a reaction member support cooperatively formingan oil pressure chamber with said rocker arm support for urging a rockerarm carried by the support into lash preventing engagement with its pushrod and valve stem, means secured to the post and cooperating with thereaction member holding it in operation position, and passageway meansdefining a vent past the post to permit the escape of air bubblesentrained in the oil.

8. A device for preventing lash in engine valves operated by a rockerarm comprising a rocker arm support having a bearing for pivotallycarrying the rocker arm, a reaction member support cooperatively formingan oil pressure chamber with said rocker arm support for urging a rockerarm carried by the support into lash preventing engagement with its pushrod and valve stem, means securing the reaction member to the post, anoil pressure conduit communicating with the pressure chamber, and an oilleakage passageway defining means forming an oil passageway from thepressure conduit past the post whereby a small amount of oil escapes tolubricate the bearlugs.

9. A valve lash preventing device comprising a first and second supportmember for pivotally carrying a rocker arm for an engine, said supportmembers defining an oil pressure chamber between them, a source forsupplying oil pressure to said pressure chamber, an oil delivery conduitconnecting between said oil source and said pressure chamber, and airremoving means located between the pressure chamber and said oil sourceremoving air entrained in the oil before it reaches the pressurechamber.

10. A valve lash preventing device comprising a first and second supportmember for pivotally carrying a rocker arm for an engine, said supportmembers defining an oil pressure chamber between them, a source forsupplying-oil pressure to said pressure chamber, an oil delivery conduitconnecting between said oil source and said pressure chamber, a postsupporting one of said members in operating position, and an annularleak down passageway between the post and member supported thereby forlubricating the valve operating gear, said passageway communicating withthe 'oil delivery conduit for the delivery of oil to the bearing surfaceof the rocker arm.

11. A valve lash preventing device comprising a first and second supportmember for pivotally carrying a rocker arm for an engine, said supportmembers-defining as'ra'rsu an oil pressure chamber between them, asource for supsingle dynamic seal between said support members whereby aminimum of restriction is ofiered to relative movement therebetween forrapid response with various oil viscosities.

12. A valve lash prevention assembly comprising a bearing member havinga cylindrical outer surface adapted to pivotally support a rocker arm inengagement with a push rod and a valve stem, at second reaction memberforming an interior cylindrical surface for receiving the bearing membertherein and coacting with the bearing member to form an oil pressurechamber, a support member adapted to carry the reaction member in anoperating position, and means delivering oil under pressure to said oilpressure chamber.

13. A valve lash prevention assembly comprising a bearing member havinga cylindrical outer surface adapted to pivotally support a rocker arm inengagement with a push rod and a valve stem, a reaction member, formingan interior cylindrical surface for receiving the bearing member to beslidably positioned therein and coacting with the bearing member to forman oil pressure chamber, a support member adapted to carry the reactionmember in an operating position, and adjustment means connected to thereaction member and threaded to the support member whereby the positionof said member may be adjusted.

14. Av valve lash prevention assembly comprising a bearing member havinga cylindrical outer surface adapted to pivotally support a rocker arm inengagement with a push rod and a valve stem, a cup shaped reactionmember having a cylindrical interior for slidably receiving the bearingmember and extending over the top of the hearing member with an openingthrough the top and coacting with the bearing member to form an oilpressure chamber, a supporting post adapted to be mounted on an engineand projecting through the opening at the top of the reaction member,means for securing the reaction 10 member to the post, and mean: fordelivering oil to the pressure chamber.

15. A valve lash preventer operable through a first stage when an enginevalve is being opened and a second stage when the valve is being closed,comprising a bean ing member adapted to be connected to pivotallysupport an actuated rocker arm, a reaction member forming an oilpressure chamber with the bearing member, an oil escape pathcommunicating with the pressure chamber permitting a controlled escapeof oil when an engine valve is being opened in the first stage and therocker arm exerts a force on the bearing member, and an oil replenishingpath communicating with the pressure chamber for the replacement of oillost through the escape path and feeding oil to the pressure chamber inthe second stage when the valve is being closed.

16. A valve lash preventing device comprising a unitary supportingcartridge having a rocker arm carrying member adapted to be connected topivotally support the rocker arm, means for holding the supportingcartridge in operating position relative to an engine, pressure chamberelements forming an expansible oil pressure chamber operativelyconnected to the carrying member, means forming an oil supply reservoirconnected to the pressure chamber, and means within the supportingcartridge maintaining a pressure within the reservoir to maintain anoperating pressure in the pressure chamber.

17. A device for preventing lash in engine valves operated by a rockerarm comprising a rocker arm support having a bearing for pivotallycarrying the rocker arm, a reaction member cooperatively forming an oilpressure chamber with said rocker arm support for urging a rocker armcarried by the. support into lash preventing engagement with its pushrod and valve stem, at post projecting from the engine to carry saidreaction member, and means adapted to be secured to the post whereby theposition of the reaction member is determined with respect to the post.

References Cited in the file of this patent UNITED STATES PATENTS2,718,219 Chayne et a1. Sept. 20, 1955

